# Populators A populator is a procedural container that distributes assets across an area according to rules. Charles called it "Houdini for normal people" in the launch webinar. The idea is right: populators expose a small fraction of Houdini-style procedural distribution to creatives who don't have a TD on call. ## Watch {% embed url="" %} ## Why it exists Building a forest by hand means dragging two hundred trees, then nudging them so it doesn't look like an orchard. AI Composer takes the prompt "create a tropical forest" and produces a populator – an area with rules about what kinds of plants live in it, how dense they are, how they're distributed. You adjust the rules; the populator regenerates. Populators show up everywhere in the product: AI Composer outputs them by default, the Build-mode asset library has populator-style content for crowds and traffic, and you can build your own from selected objects. ## What a populator looks like in the product In the viewport, a populator has a footprint outline (a rectangle, polygon, or curve) that defines its area. Inside the footprint, individual procedural instances of assets get distributed. ![Populator Contents panel with Targets (Ignore masks / Ignore surfaces), a Density slider, and a list of Asset rows with per-asset size / distribution / count controls](/files/AbnOC58ENx3WHFnEZjAV) Click the populator's footprint to select it. The contextual menu opens a populator-content panel (different from the per-object contextual menu) with: * **Footprint shape** – rectangle, polygon, curve. Drag the corners to resize. * **Asset list** – every asset type the populator distributes, with a density slider per asset. Add new asset types by dragging into the list; delete by clicking the trash icon. * **Density** – overall scaling for instance count. * **Layout** – grid, scattered, clustered. The default is scattered for natural environments; grid for cities. * **Culling and target** – exclude or target specific surfaces (e.g. only spawn instances above a terrain height). Procedural instances inside a populator are not individually editable in the viewport. To customize one, drag it out of the populator first; then it becomes a regular object. ## How populators connect to the rest ```mermaid flowchart TD A[AI Composer prompt] -->|outputs| B[Populator] C[Manual creation from selection] -->|outputs| B D[Library populator templates] -->|drag in as| B B -->|footprint defines| E[Area] B -->|asset list defines| F[What appears] B -->|density slider tunes| G[How much] B -->|each instance feeds| H[Visualizer auto-prompt] ``` A populator's name (e.g. "tropical forest", "city block", "wedding crowd") shows up directly in the visualizer's auto-prompt. Renaming a populator from `populator-3` to `dense rainforest understorey` changes the prompt the model receives without you touching the prompt block. See [How the visualizer thinks](/overview/concepts/how-the-visualizer-thinks.md). Roads, paths, and other linear assets dropped on top of a populator suppress instances underneath them. The webinar demo showed this directly: dropping a road through a forest populator clears trees from the road's footprint automatically. This is the populator behaving like Houdini's boolean culling, with no hand-holding. ## When to reach for it Three signals: * **You need fifty or more of the same kind of object.** Crowds, vegetation, traffic, dense urban features. Manual placement falls apart past a couple dozen. * **You want the distribution to look natural.** A forest dragged in by hand looks like an orchard. A populator with scattered layout and varied density looks like a forest. * **You want to iterate the look.** Change the asset mix or density slider and the populator regenerates in seconds. Doing the same thing manually means re-dragging. When not to reach for it: * **One specific hero object.** Drag the hero in directly. Populators are for fields of stuff, not for the Lambo in your commercial. * **You need pixel-precise placement of every instance.** Populators distribute procedurally; you don't get to say "this exact tree, two meters left". Convert specific instances to objects if you need that. ## Locking populator instances {% hint style="warning" %} Don't try to lock individual procedural instances inside a populator. The lock will be silently overridden the next time the populator regenerates (which can happen on density-slider changes). Lock the whole populator instead, or convert the specific instance to an object first by dragging it out. {% endhint %} ## Related * [Build-mode populators page](/build/populators.md) * [AI Composer](/build/ai-composer.md) * [How the visualizer thinks](/overview/concepts/how-the-visualizer-thinks.md) * [Scene Outliner](/build/scene-outliner.md) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://help.intangible.ai/overview/concepts/populators.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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